Introduction

One of my favorite books as a kid was The Way Things Work by C
Van Amerongen (Simon and Schuster), which
my parents gave to me for Christmas one year. This book describes how
all sorts of things are put together. Since I spent a lot of time
taking things apart to figure
out how they worked, my parents had damage control partly in mind in
giving me the book. I, on the other hand, was particularly happy about seeing
assembly drawings of things I couldn't get my hands on, like jet
engines, or that were small and hard to figure out, like a phonograph
cartridge.

The Way Things Work is a wonderful source if you want to see how
everyday things are constructed, and I highly recommend it. However,
it does not describe the underlying physics principles involved in a
given device.
Most of the things we use in our modern, technological society are
based on a few, basic concepts of physics. This reflects the goal of
physics: to describe natural laws, experimentally studied, with a
basic set of widely-applicable concepts. The goal of this web book is
demonstrate this broad applicability to a wide variety of things we
experience every day.

Traditional introductory physics courses are tought subject by subject, in a
roughly historical order. You start with kinematics (the mathematical
description of motion), move on to dynamics (the laws relating
motion to forces), then thermodynamics (laws relating energy, heat and
temperature), then electricity and magnetism, usually a little optics,
and wind up with atomic physics (mainly the interaction of light and
atoms). This takes a school year, and you're best off having a few
calculus courses under your belt before you start so you can use
calculus in the physics class. This is clearly a big project.

This web book takes a different approach --- rather than describing the
laws of physics and concocting examples along the way, as you do in a
physics course, it takes examples from everyday life and describes the
relevant physics. Of course, it makes sense to start with
simpler physics and build up to more complicated things. If you read
the web book from front to back, you will be introduced to new physical
concepts in an orderly fashion. If you use this web book as a
reference, you may have to look back at previous examples to fill in
some of the physics, and it's cross-referenced for that reason.

It is very difficult to discuss physics quantitatively without using some
mathematics. I assume that you know some algebra and
trigonometry, but may not know or remember calculus. Since calculus
was, in fact, developed for use in physics, I will mention where it
comes in from time to time.

The various topics all stand on their own, but if you'd like to see them categorized, here are the general areas that they fall under: